Concrete anchor

ABSTRACT

An anchor particularly adapted to be embedded into a concrete construction for suspension of a ceiling panel, duct or the like, includes a base which receives inserts that have an axial threaded bore. The base is open at its lower end and can receive a threaded rod by virtue of ratcheting inserts received within the base. The inserts and base are particularly shaped to prevent jam and ease of insertion of the rod in the anchor. The anchor also has a head flange that sits above a plurality of fasteners secured to the anchor which is used to simultaneously drive the fasteners into a form for the concrete member. The fasteners are connected to the anchor extending in generally parallel and spaced relation to the anchor. The fasteners can be held by a support or sleeve-like holder which surrounds at least a portion of the base of the anchor or they can be attached to the base of the anchor. The fasteners project downwardly through the bottom of the anchor for driving into the form board.

BACKGROUND OF THE INVENTION

This invention relates to an anchoring device, and more particularly, toa concrete anchor which is embedded in a concrete ceiling for suspensionof a ceiling panel, electrical wiring pipe, air conditioning device, orthe like.

Concrete anchors are well known in the prior art. They provide a meansto hang building systems from concrete ceilings. The anchors areinstalled prior to pouring the concrete into a form that creates thelevel of a building. The concrete anchors are located in the ceiling atthe proper locations by attaching them to the form that supports theconcrete as it is hardening. The best concrete anchors are inexpensiveto make and assemble, are quickly placed in the proper position on theform, are resistant to cement entering into the working mechanisms ofthe anchor, and can accept a variety of sizes of threaded rods forsupporting the building elements. U.S. Pat. No. 1,940,545, issued in1933 to Holmes, teaches an early concrete anchor made from cast iron andis hereby incorporated by reference. U.S. Pat. No. 3,405,497, issued in1968 to McNair, teaches a modern concrete anchor made from both metaland plastic components to reduce the cost of manufacture and is herebyincorporated by reference. The use of plastic components alsofacilitates identification of the anchors by using differing colors ofplastic which can be used to instruct users about the size of rod thatcan be used with the anchor. U.S. Pat. No. 4,211,048, issued in 1980 toNaka, also teaches a concrete anchor made from both metal and plasticcomponents and is hereby incorporated by reference. The Naka patentfocused on improving the manner in which the anchor is connected to theform. Naka shaped the parts, particularly the top of the anchor, so thatthe nails that attach the anchor to the form can be drivensimultaneously. Published Japanese Patent Application 5-230893, filed in1982, teaches a concrete anchor where the anchor receiving portion ismade with a plurality of internal diameters so that one anchor canreceive different sized threaded rods. U.S. Pat. No. 6,240,697, issuedin 2001 to Thompson et al, also teaches a concrete anchor made from bothmetal and plastic components that can receive threaded rods of multiplediameters, the contents of which are hereby incorporated by reference.

A problem with all of the concrete anchors taught by the prior art isthat the rod needs to be threaded into the anchor. This slows downinstallation of the suspended system and can be difficult as the user isgenerally working from below. There are a number of systems in the priorart where a threaded member is received by a slip nut or other device tohold the threaded member in place without having to thread the rod intothe slip nut. U.S. patent application Ser. No. 13/531,159, filed Jun.22, 2012, teaches an automatic take-up device that has threaded insertsthat can receive a threaded rod without having to rotate the threadedrod into the device, the contents of which are hereby incorporated byreference.

The present invention provides a concrete anchor with inserts that canreceive a threaded rod without having to thread the rod into the devicethat can be used with confidence in a concrete anchor where the anchorwill be encapsulated by concrete and otherwise inaccessible to the userexcept for inserting the rod into place.

SUMMARY OF THE INVENTION

The present invention provides an anchor device for connecting a rod toa first structural member, in particular for suspending rods from aconcrete ceiling, where the anchor device is encapsulated in concreteexcept for its bottom which is exposed, and yet can reliably grasp andhold a threaded rod without having to thread the rod into the member.This object is achieved by using ratcheting inserts received within theanchor.

It is an object of the present invention to provide a concrete anchorwhich allows for the insertion of rods of different sizes withoutrequiring the rods be threaded into the concrete anchor. This object isachieved by forming the inserts with a rod receiving bore havingmultiple internal diameters.

It is another object of the present invention to provide a concreteanchor which is simple in construction and easy to manufacture, and yetcan receive a sufficient length of a threaded rod without jamming so asto reliably hold the threaded rod.

It is also an object of the present invention to provide a concreteanchor that is easily installed in the form for the concrete member.This object is achieved by forming the insert receiving bore of theanchor with a bottom ledge and lip. This object is also achieved byforming the insert receiving bore with a smaller diameter mid-section.This object is also achieved by forming the inserts withfrusto-spherical surfaces that engate the lower portion of the insertreceiving bore. The object is also achieved by forming the inserts withexternal tabs that interface with notches in the housing and forming thetabs partially with sloping surfaces where they interface with thenotches.

In accordance with the present, there is provided an anchor adapted tobe embedded into a concrete construction for suspension of a ceilingpanel, duct or the like. The anchor includes a base which receivesinserts that have an axial threaded bore. The base is open at its lowerend. The anchor also preferably has a head flange that sits above aplurality of fasteners secured to the anchor which is used tosimultaneously drive the fasteners into a form for the concrete member.The fasteners are connected to the anchor extending in generallyparallel and spaced relation to the anchor. The fasteners can be held bya support or sleeve-like holder which surrounds at least a portion ofthe base of the anchor or they can be attached to the base of theanchor. The fasteners project downwardly through the bottom of theanchor for driving into the form board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of the presentinvention.

FIG. 2 is an exploded, perspective view of the first, preferredembodiment of the present invention.

FIG. 3 is a top view of the base of the first, preferred embodiment ofthe present invention.

FIG. 4 is a sectional side view of the base of the first, preferredembodiment of the present invention.

FIG. 5 is a top view of the cap of the first, preferred embodiment ofthe present invention.

FIG. 6 is a sectional, side view of the cap of the first, preferredembodiment of the present invention.

FIG. 7 is a top view of the compression spring of the first, preferredembodiment of the present invention.

FIG. 8 is a sectional, side view of the compression spring of the first,preferred embodiment of the present invention.

FIG. 9 is a top view of the inserts of the first, preferred embodimentof the present invention.

FIG. 10 is a side view of a pair of the inserts of the first, preferredembodiment of the present invention.

FIG. 11 is a top view of the inserts inserted into the base of thefirst, preferred embodiment of the present invention.

FIG. 12 is an exploded sectional, side view of the first, preferredembodiment of the present invention.

FIG. 13 is sectional, side view of the first, preferred embodiment ofthe present invention attached to a wood form.

FIG. 14 is a sectional, side view of the first, preferred embodiment ofthe present invention installed in a concrete form with the form boardremoved and a threaded rod inserted into the concrete anchor.

FIG. 15 is a sectional, side view of the first, preferred embodiment ofthe present invention installed in a concrete form with the form boardremoved and a threaded rod of differing diameter than the threaded rodshown in FIG. 14 inserted into the concrete anchor.

FIG. 16 is a perspective view of a second preferred embodiment of thepresent invention.

FIG. 17 is an exploded, perspective view of the second, preferredembodiment of the present invention.

FIG. 18 is a top view of the holder of the second, preferred embodimentof the present invention.

FIG. 19 is a sectional side view of the holder of the second, preferredembodiment of the present invention.

FIG. 20 is a top view of a washer of the second, preferred embodiment ofthe present invention.

FIG. 21 is a sectional, side view of the washer of the second, preferredembodiment of the present invention.

FIG. 22 is a top view of the compression spring of a first, preferredembodiment of the present invention.

FIG. 23 is a sectional, side view of the compression spring of a first,preferred embodiment of the present invention.

FIG. 24 is a top view of the plate used with the cap of the second,preferred embodiment of the present invention.

FIG. 25 is a sectional side view of the plate used with the cap of thesecond, preferred embodiment of the present invention.

FIG. 26 is a top view of the cap of the second, preferred embodiment ofthe present invention.

FIG. 27 is a sectional, side view of the cap of the second, preferredembodiment of the present invention.

FIG. 28 is a top view of the inserts of the second, preferred embodimentof the present invention.

FIG. 29 is an exploded, top view of the inserts of the second, preferredembodiment of the present invention.

FIG. 30 is a sectional, side view of the inserts of the second,preferred embodiment of the present invention.

FIG. 31 is a top view of the inserts inserted into the base of thesecond, preferred embodiment of the present invention.

FIG. 32 is a partial, exploded sectional, side view of the second,preferred embodiment of the present invention.

FIG. 33 is sectional, side view of the second, preferred embodiment ofthe present invention attached to a wood form.

FIG. 34 is a sectional, side view of the second, preferred embodiment ofthe present invention installed in a concrete form with the form boardremoved and a threaded rod inserted into the concrete anchor.

FIG. 35 is a sectional, side view of the second, preferred embodiment ofthe present invention installed in a concrete form with the form boardremoved and a threaded rod of differing diameter than the threaded rodshown in FIG. 34 inserted into the concrete anchor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention teaches a concrete anchor or anchor 1 that isattached to a form 2 with nails 3 and can receive a threaded rod or tierod or threaded bolt or vertical bolt 4. FIG. 1 shows a first, preferredembodiment of the concrete anchor 1 of the present invention. FIG. 13shows the anchor 1 connected to form 2. FIG. 14 shows the anchor 1embedded in a concrete member that can be considered a first structuralmember.

For clarity and convenience, the concrete anchor 1 of the presentinvention is described in a single, most common, orientation (except asnoted otherwise) in which a top 5 faces up and a bottom 6 faces down.The concrete anchor 1 can, nevertheless, be installed in essentially anyorientation, so that the top 5 can face down or to the side and thebottom 6 can face up or to the side so long as there is sufficienttension generated between the threaded rod 4 and the concrete anchor 1for the anchor to grasp the threaded rod 4.

As shown in FIGS. 12 and 15, the concrete anchor 1 of the presentinvention is provided with inserts 7 with concavities forming aninterior rod receiving bore 8. The interior receiving bore 8 receivesthe threaded rod 4. The use of inserts 7 allows the threaded rod 4 to beinserted into the concrete anchor 1 without threading or rotating thethreaded rod 4 into the anchor 1.

The inserts 7 are formed and arranged so that they can grasp and hold atie rod 4 received in the concrete anchor 1 that is typically subject toa tension load either from the weight of the tie rod 4 itself or fromthe weight of a member attached to the tie rod 4. The concrete anchor 1is also preferably formed with a compression member 9 and narrowing baseor housing 10 that pushes the inserts 7 downwardly and around thethreaded rod 4 to grasp the threaded rod 4. The compression member 9 isshown by itself in FIGS. 7 and 8. The tie rod 4, inserts 7 and the base10 are formed such that when the tie rod 4 moves downwardly with respectto the housing or base 10, the inserts 7 will be pulled downwardly inthe base or housing 10 as well. As shown in FIG. 4, the tension on thetie rod 4 combined with the narrowing in the lower portion 17 of theinsert receiving bore or base bore 11 of the housing 10 causes aconstriction of the insets 7 about the tie rod 4 forcing them to graspand hold the tie rod 4.

When a tie rod 4 is first inserted up into the base 10, the upwardmovement of the tie rod 4 forces the inserts 7 apart from a constrictedposition. The constriction is preferably caused by the downward force ofgravity, or tension on the rod 4, and also preferably by a compressionmember 9 placed above the inserts 7, combined with the narrowing in thelower portion 17 of the insert receiving bore 11 of the housing 10. Theinterface between the surface of the tie rod 4 and the inserts or insertsegments 7 creates a ratcheting action as the tie rod 4 is pushed up andthe insert segments 7 move up and out laterally, allowing the tie rod 4to be inserted as far as needed into the housing 10 for installation.

Rather than being screwed into the inner bore or interior rod receivingbore 8, the threaded rod 4 is preferably pushed in without rotation andthe inserts 7 react by moving apart and together, ratcheting when thethreaded inner rod receiving bore 8 interfaces with a threaded bolt 4.The compression member 9 allows the inserts 7 to move up within thehousing 10, and the upwardly-widening base bore 11 allows the insertsegments 7 to move apart. This allows the threaded bolt 4 to be insertedinto the inner bore 8, and as the threaded bolt 4 and the threadedportions 12 of the inner surface 13 of the inserts 7 slide against eachother, the inserts 7 are moved up and outwardly and down and inwardlyrepeatedly, the inward motion urged by the compression member 9 and thenarrowing base bore 11 in the housing 10. The threaded bolt 4 can onlybe inserted in one direction because when it is pulled down, thedownwardly-narrowing outer base bore 11 forces the insert segments 7against the threaded rod 4 so that the threaded bolt 4 and the threadedportion 12 of inner surface 13 of the inserts 7 interlock as if thethreaded bolt 4 had been screwed into a conventional solid nut.

As shown in FIGS. 2 and 10, the interior receiving bore 8 of the inserts7 is preferably made with a lower portion 14, having a first selecteddiameter, an upper portion 15 having a second selected diameter, and amiddle portion 16 or portions having differing selected diameters. Thisallows the concrete anchor to receive threaded rods 4 of differing,selected diameters. Preferably, the lower portion 14 receives the rod 4with the largest diameter, and the upper portion 15 receives the rod 4with the smallest diameter.

The inserts 7 are received in the base or housing 10 that contains themby the insert receiving or base bore 11 of the base or housing. The base10 is preferably a seamless, unitary member. The lower portion 17 of thebase bore 11 narrows to cause the inserts 11 to constrict around thethreaded rod 4.

The concrete anchor 1 of the present invention preferably has fourinserts 7. Greater or lesser numbers of inserts are possible, but fouris preferred.

As shown in FIG. 14, the inserts 7 are designed to grasp a preferablyvertical tie rod or threaded bolt 4. Preferably, vertical tie rod 4 hasthreads 18 and is at least threaded where it is grasped by insertsegments. Vertical tie rod 4 can be wholly threaded, partially threaded,or unthreaded, although if its unthreaded it is preferable to havegrooves 19 on its surface that can mate with similar grooves 20 (shownin FIG. 12) on the inserts 7 for achieving design load values, althoughalternate methods of grasping the tie rod 4 by the inserts 7 isencompassed within the invention. The inserts 7 preferably surround thetie rod or threaded bolt 4, but with gaps between the inserts 7.

As shown in FIG. 9, each insert 7 preferably has first and secondsubstantially planar sides 21 and 22 which are preferably perpendicularto the top surface 23. The first and second substantially planar sides21 and 22 are preferably orthogonal to each other.

As shown in FIG. 2, each insert 7 preferably has a rough, threaded,concave inner bore-defining surface 24 that extends downward from thetop or near the top of the insert and connects the first and secondsubstantially planar sides 21 and 22. Preferably, each interiorbore-defining surface 24 is primarily a section of a rough, threaded,right circular cylindrical surface that defines the inner bore 8.

As shown in FIG. 9, each insert 7 preferably has a base-bore interfacingsurface or outer wall 25 that extends downward from the top surface 23.The base-bore interfacing surfaces 25 preferably taper from the topsurface 23 of the inserts to the bottom edge 26 of the insert 7,reducing the cross-section of each insert from the top surface 23 to thebottom edge 26. As shown in FIG. 10, preferably, the general shape ofthe upper portion 27 of the base-bore interfacing surface 25 of theinserts is collectively that of a cylinder. In one preferred embodimentof the invention shown in FIGS. 16-35, the inserts 7 are formed withtabs 28 splayed circumferentially on the base-bore interfacing surface25. As shown in FIGS. 10 and 30, the lower portion 29 of the base-boreinterfacing surface 25 of the inserts 7 curves or slopes inwardly.

The height of the inserts 7 and the lengths of the threaded portions 12of the inserts 7 is sufficient to grasp enough of the tie rod orthreaded bolt 4 for a secure connection by connecting to multiple turnsof the thread or grooves 19 of the rod or bolt 4.

Preferably, the inserts 7 are retained within the base bore 11 by acompression member 9. In one preferred embodiment, the compressionmember 9 preferably comprises a lower hard washer 30 and an upper softwasher 31. The soft washer 31 is preferably made from a resilientmaterial like rubber that, when compressed, stores energy and expandswhen compression forces are released. Preferably, the soft washer 31 ismade from soft, quick-recovery, super-resilient polyurethane foam. Thesoft washer 31 functions like a standard metal compression spring and aspring could be used, but the foam washer is preferred. The lower washer30 is preferably made from steel.

As shown in FIG. 13, the concrete anchor 1 is preferably attached to thewooden form 2 by means of fasteners 3, preferably nails 3 that areinserted through openings 32 in the concrete anchor 1 and driven intothe form board 2. The fasteners 3 are preferably angularly spaced aroundthe concrete anchor 1, and are driven by driving the head flange 33 ofthe concrete anchor 1 which translates the force to the fasteners 3simultaneously. The fasteners 3 extend downwardly from the lower surface34 of the head flange 33 in preferably parallel and spaced apartrelationship.

In the first preferred embodiment of the present invention, shown inFIGS. 1-15, the base or housing 10 is formed with openings 32 forgrasping and holding the fasteners 3, and the bottom 35 of the base orhousing 10 is in contact with the top surface 36 of the form board 2 forthe concrete member 37.

As shown in FIG. 4, in the first preferred embodiment, the base bore 11of the housing 10 has a first sliding surface 38 disposed at an angle tothe longitudinal axis 39 of the anchor that forms part of the lowerportion 17 of the base bore or insert receiving bore 11. This firstsliding surface 38 is preferably frusto-conical in shape.

Above the base first sliding surface 38 is an upper housing wall 40 withan angle of ascension much greater than the base first sliding surface38. This upper housing wall 40 is preferably vertical.

In the first preferred embodiment shown in FIGS. 1-15, inwardly from thefirst sliding surface 38, the base is formed with a bottom base-boreledge 41. Inwardly from bottom ledge 41 towards the axis 39 of theanchor 1, a lip 42 is provided with an angled, ascending face 43 towardsthe longitudinal axis 39 of the anchor. The base-bore ledge 41 and lip42 stabilize the inserts 7 in the housing which have interior taperingsurfaces 44 that correspond to the angle of the lip 42.

In the first preferred embodiment shown in FIGS. 1-15, when the inserts7 are vertical and sitting at the bottom or as far down in the base bore11 of the housing as they can go, and in their constricted state, insertfirst sliding surfaces 45 located at the base of the inserts 7 mate withthe housing first sliding surface 38. In the first preferred embodiment,the insert first sliding surface 45 is shorter than the housing firstsliding surface 38 (that is to say that they do not extend as farupwardly or away from the longitudinal axis of the anchor 39) and theinserts 7 can travel upwardly along the housing first sliding surface38.

Above the insert first sliding surface 45, the inserts 7 are formed withinsert walls 25 with an angle of ascension much greater than the insertfirst sliding surface 45. The upper insert walls 25 are preferablyvertical. In the first preferred embodiment, when the inserts arevertical and sitting at the bottom of the housing, and in theirconstricted state, the upper insert walls 25 are located away from thehousing upper walls 40.

In the first preferred embodiment, a compression member 9 is preferablylocated between the inserts 7 and a cap 46 which is attached to the topof the housing or base 10. In the first preferred embodiment the cap 46is threaded onto the housing 10. The cap 46 is formed with the headflange 33 that extend over the heads 47 of the fasteners 3. The fastenerheads 47 are in contact with the bottom 48 of the cap to translatedriving forces applied to the top 49 of the cap 46 to the fasteners 3.The fasteners 3 are formed with pointed tips 50 for making it easier todrive the fasteners 3 into the form 2. Aligned tabs 51 at the base andnear the top of the housing 10 hold the fasteners 3 to the housing 10.

In the second preferred embodiment of the present invention, shown inFIGS. 16-35, the base or housing 10 is received by a holder 52. As bestshown in FIG. 19, the holder 52 is formed with openings 32 for graspingand holding the fasteners 3, and the bottom 53 of the holder is incontact with the form board 2 for the concrete form 2. The holder 52separates the base 10 from the top surface 36 of the form board 2. Theholder 52 is formed with a base receiving bore 54 that has a basereceiving ledge or shoulder 55 substantially above the bottom of theholder 53. The bottom of the base 35 interfaces with the shoulder 55 inthe base receiving bore 54. The holder 52 can be made from plastic whichis much cheaper to manufacture than the base 10 which needs to besufficiently strong to resist the outward pressure generated by theinserts 7 when a tension load is applied to the threaded rod 4 receivedin the anchor 1. With the use of the holder 52, the base 10 can be madeshorter and from less material, thus reducing its cost of manufacture.The base receiving bore 54 of the holder is shaped so that the base 10when inserted into the holder 52 with the bottom of the base 35 touchingthe shoulder of the holder 55, the base 35 protrudes slightly above andbeyond the top of the holder 52. The base receiving bore 54 of theholder 52 is shaped to create a close friction fit between the holder 52and the base 10.

In the second preferred embodiment, the insert receiving bore or basebore 11 of the housing 10 has a first sliding surface 38 disposed at anangle to the longitudinal axis of the anchor 39. This first slidingsurface 38 is preferably frusto-conical in shape, but it could also befrusto-spherical.

Above the base first sliding surface 38 is a middle housing wall 56 withan angle of ascension much greater than the base bore first slidingsurface 38. This middle housing wall 56 is preferably vertical. Themiddle housing wall 56 extends upwardly for only a short distance, untilit reaches a shoulder 57 which has an angle of ascension that is lessthan the middle housing wall 56. The shoulder 57 is preferably anannular ledge 58 that is orthogonal to the longitudinal, central axis 39of the anchor 1. Above the annular ledge 58 an upper housing wall 40extends at an angle of ascension much greater than the first slidingsurface 38 of the base 10. This upper housing wall 40 is preferablyvertical. The middle housing wall 56 is preferably cylindrical in shapeand has a diameter large enough to contain the lower portions of theinserts 7 in their constricted position.

In the second preferred embodiment, below the base first sliding surface38, the wall of the base-bore 11 descends at an angle of descent that isgreater than the angle of base first sliding surface 38. This angle ispreferably vertical or aligned with the axis of the anchor, creating alower housing wall 59.

In the second preferred embodiment, when the inserts 7 are vertical andsitting at the bottom of the housing 10, and in their constricted state,insert first sliding surfaces 45 located at the base of the inserts 7contact the base first sliding surface 38. In the second preferredembodiment, the insert first sliding surface 45 can travel upwardlyalong the base first sliding surface 38. In the second preferredembodiment, the insert first sliding surface 45 is frusto-spherical andin contact with the housing or base first sliding surface 38 which isfrusto-conical. The lower portions of the inserts 7 collectively havethe geometry of a spherical segment—a spherical cap with the toptruncated, or a spherical frustum. The inserts 7 are inserted in thebase bore 11 of the housing 10. The lower sliding surfaces 45 of theinsert segments 7 are able to rotate or swing to be in contact with thefirst sliding surface 38 of the base 10 due to their rounded profile.

Above the insert first sliding surface 45, the inserts are formed withinsert walls with an angle of ascension much greater than the insertfirst sliding surface 45. The upper insert walls 25 are preferablyvertical. In the first preferred embodiment, when the inserts 7 arevertical and sitting at the bottom of the housing 35, and in theirconstricted state, the upper insert walls 25 are located away from theupper walls of the housing 40 and in contact with the middle wall 56 ofthe housing or base 10.

As shown in FIGS. 28-30, the inserts 7 are generally formed with aninner bore defining arc 60 and an outer wall defining arc 61. The outerwall defining arc 61 of each insert in the second preferred embodimentis preferably interrupted by an insert tab 28 that projects from theconvex outer wall defining arc or edge 61. The insert tab 28 ispreferably formed as an integral part of the insert 7, rather than as aseparate part attached to the insert 7. The insert tab 28 extends onlypartially down the outer wall 25 of the insert 7.

In the second preferred embodiment, the base has a top edge 63. The topedge is preferably flat. The top edge 63 of the housing 10 and portionsof the upper wall 40 are notched with a number of indentations 64 thatclosely match the tabs 28 on the inserts. The notches 64 extenddownwardly to the notch ledges 65. Each tab preferably fits in anindentation 64, but does not extend outside the housing 10. Theinterlock between the insert tabs 28 and the indentations 64 preventsthe inserts from rotating around the central axis 39. The interfacebetween the tabs 28 and the indentations 64 also help to stabilize theinserts 7, helping to keep them level especially when a threaded rod 4is inserted into the inner bore 24.

The preferred embodiment of the insert tab 28 has a multiple steppedprofile. The upper portion 66 of the insert tab 28 extends sufficientlyaway from the insert upper wall 25 to be received in the notch orindentation 64 of the upper wall 40 of the base 10 when the inserts arein their constricted orientation resting at the base of the housing 10.A middle portion 67 of the insert tab 28 extends away from the insertupper wall 25 less than the upper portion of the insert tab 28. Themiddle portion 67 extends sufficiently away from the upper wall 25 ofthe insert 7 that when the inserts 7 are in their constrictedorientation or state the outer surface 68 of the middle portion 67 ofthe tab 28 interfaces with the upper wall surface 40 of the base 10below the notch 64. The insert tabs 7 are also formed with a lowerportion 69 that angles towards the upper wall 25 of the insert 7 untilthe tab reaches the upper wall 25, creating a ramped surface 70. Theramped surface 70 of the lower portion 69 of the insert tab 28 ispreferably planar. This represents the lower extent of the insert tab28. The insert tabs 28 are able to at least partially fit in the notches64 in the wall of the housing 10. The insert tabs 28 have acircumferential extent or width that is less than the circumferentialextent of the notches 64 or indentations in the base 10.

The inserts 7 are formed so that when a threaded rod 4 is inserted intothe anchor 1 and pushes the inserts 7 upwardly, the outer wall orsurface 68 of the middle portion 67 of the insert tabs 28 can bereceived in the notches 64 in the housing above the ledge 65, and theouter wall or surface 70 of the lower portion of the insert tab 69 cancontact the edge 71 of the ledge 65 of the housing notch 64 where itinterfaces with the upper wall 40 of the housing 10. The upper portions66 of the insert tabs 28 extend sufficiently toward the housing wall 40such that the upper portions 66 of the tabs 28 are received in the notch64 when the inserts 7 are in their constricted state and resting at thebase of the housing 10, but the upper portions of the tab 66 are spacedsufficiently from the housing 10 that when the inserts 7 are pushedupwardly and tipped or translated outwardly the upper portions 66 of theinsert tabs 7 can be inserted further into the notches 64.

In the second preferred embodiment, a compression member 9 is preferablylocated between the inserts 7 and cap 46 which is attached to the top ofthe housing or base 10. In the second preferred embodiment the cap 46 isformed with an annular descending, shouldered flange 72 that can clamponto the annular flange 73 of the base 10. The cap 46 is so large thatit extends over the heads of the fasteners 47. The fastener heads 47 arein contact with the bottom of the flange 74 of the base 10 to translatedriving forces applied to the top of the cap 49 which rests on theflange 74 of the base 10 to the fasteners 3. The fasteners 3 are formedwith pointed tips 50 for making it easier to drive them into the form 2.Bosses and tabs 51 in the holder 52 hold the fasteners 51 to thehousing. The cap 46 receives a plate 75 made of metal that helps totranslate the force exerted on the cap 46 to the head flange 33 of thebase 10. The cap 46 is preferably made of plastic.

The first sliding surfaces 38 of the housing are preferably set at thesame angle as the thread angle of the rod 4.

In the preferred embodiments, the inserts 7 are made with flat tops 23and in one preferred embodiment are compressed by a member 9 with a flatsurface so that it allows the tie rods 4 to be inserted with a minimalrisk of jamming the take-up device 1 because the inserts 7 are held inplace by a flat, hard washer 30 above, which interfaces with the flatsurfaces 23 at the top of the inserts 7 to stabilize them as they expandaway from and constrict towards the central vertical axis 39 of theanchor 1.

The top surface 23 of the inserts 7 need not be planar, but it isgenerally advantageous to maximize the area of the top surface 23because the top surface 23 is where the inserts are pushed down bycompression member 9 which helps to prevent the inserts 7 from rotatingtoo far out of their upright orientation when the tie rod 4 pushes themupwardly and outwardly when it is installed, and thus the inserts 7 areappropriately positioned to grasp the tie rod 4 as firmly as possiblewhen the tie rod 4 is in tension.

In use, the concrete anchor 1 is placed on a form 2 at a selectedposition, and then the top 5 of anchor 1 is hammered to drive thefasteners 3 into the form 2 until the bottom 6 of the anchor 1 bearsagainst the top surface 36 of the form 2. Concrete 37 is then castaround the concrete anchor 1. The hardened concrete cast around theanchor 1 can be considered a first structural member to which the rod 4is connected by means of the anchor 1. After the concrete 37 hashardened, the form 2 is removed. Thereupon, the interior bore 24 isexposed through the concrete slab 37 as well as the bottom 35 of thehousing or base 10. The housing or base 10 can be colored to indicatethe size or sizes of rods 4 that can be received by the concrete anchor1. The portions of the fasteners 3 which project beyond the bottom 35 ofthe base or housing 10 should be cut off to prevent them from being ahazard. A suspension bolt or threaded rod 4 can be then inserted intoand grasped by the concrete anchor 1, and various building members canbe suspended from the threaded rod 4.

I claim:
 1. A connection between a rod, an anchor, and a firststructural member, the connection comprising: a. the first structuralmember; b. the rod, having a thread with a thread angle; and c. theanchor, connecting the first structural member to the rod, the anchorincluding a housing, the housing having a bottom and a top, and theanchor having a longitudinal central axis extending through the bottomand the top of the housing, the housing having an insert receiving borethat opens through the bottom of the housing, the insert receiving borehaving a narrowing lower portion closer to the bottom than the top ofthe housing; and wherein a plurality of inserts are disposed in theinsert receiving bore and contained securely within the housing, each ofthe inserts has a base bore interfacing surface that interfaces with thenarrowing lower portion of the insert receiving bore of the housing,wherein each insert has a concave inner surface and the plurality ofconcave inner surfaces form a generally tubular interior rod receivingbore that receives a portion of the rod, and the inserts are sized withrespect to the housing such that when the rod is received in theinterior rod receiving bore and engages the inserts and moves toward thebottom of the housing, the inserts will be pulled toward the bottom ofthe housing, and the narrowing in the lower portion of the insertreceiving bore causes a constriction of the inserts about the rodforcing them to grasp and hold the rod, the lower portion of the insertreceiving bore of the housing has a base-bore first sliding surfacedisposed at an angle to the longitudinal, central axis of the anchor andwhen the rod is inserted into the interior rod receiving bore and movestoward the top of the housing, the inserts can be moved away from eachother and from the longitudinal, central axis of the housing, allowingthe rod to be inserted farther into the housing and towards the top ofthe housing; and wherein d. the first sliding surface of the housing isset at the same angle as the thread angle of the rod.
 2. The connectionof claim 1, wherein: the interior rod receiving bore is formed withmultiple diameters such that anchors of different diameters can bereceived by the inserts.
 3. The connection of claim 1 wherein: the firststructural member is a hardened concrete member, and the anchor isembedded the hardened concrete member.
 4. A method of forming theconnection of claim 1 comprising the steps of: a. embedding the anchorin the first structural member; and b. inserting the rod into theinterior rod receiving bore of the anchor.
 5. A connection between arod, an anchor, and a first structural member, the connectioncomprising: a. the first structural member; b. the rod; and c. theanchor, connecting the first structural member to the rod, the anchorincluding a housing, the housing having a bottom and a top, and theanchor having a longitudinal central axis extending through the bottomand the top of the housing, the housing having an insert receiving borethat opens through the bottom of the housing, the insert receiving borehaving a narrowing lower portion closer to the bottom than the top ofthe housing; and wherein a plurality of inserts are disposed in theinsert receiving bore and contained securely within the housing, each ofthe inserts has a base bore interfacing surface that interfaces with thenarrowing lower portion of the insert receiving bore of the housing,wherein each insert has a concave inner surface and the plurality ofconcave inner surfaces form a generally tubular interior rod receivingbore that receives a portion of the rod, and the inserts are sized withrespect to the housing such that when the rod is received in theinterior rod receiving bore and engages the inserts and moves toward thebottom of the housing, the inserts will be pulled toward the bottom ofthe housing, and the narrowing in the lower portion of the insertreceiving bore causes a constriction of the inserts about the rodforcing them to grasp and hold the rod, the lower portion of the insertreceiving bore of the housing has a base-bore first sliding surfacedisposed at an angle to the longitudinal, central axis of the anchor,and above the base first sliding surface is a middle housing wall, andwhen the rod is inserted into the interior rod receiving bore and movestoward the top of the housing, the inserts can be moved away from eachother and from the longitudinal, central axis of the housing, allowingthe rod to be inserted farther into the housing and towards the top ofthe housing; d. the inserts are formed with lower portions where theshape of the base bore interfacing surface causes the insert to taper toa bottom edge of the insert; and e. the middle housing wall has adiameter large enough to contain the lower portions of the inserts whenthere is a constriction of the inserts about the rod and the insertsgrasp and hold the rod; f. the base-bore first sliding surface isfrusto-conical in shape; and g. the base bore interfacing surface isfrusto-spherical where the base bore interfacing surface makes contactwith the base-bore first sliding surface.
 6. The connection of claim 1,wherein: the interior rod receiving bore is formed with multiplediameters such that anchors of different diameters can be received bythe inserts.
 7. The connection of claim 1 wherein: the first structuralmember is a hardened concrete member, and the anchor is embedded thehardened concrete member.
 8. A method of forming the connection of claim1 comprising the steps of: a. embedding the anchor in the firststructural member; and b. inserting the rod into the interior rodreceiving bore of the anchor.